USA Swimming has suspended Michael Phelps for six months due to a violation of the organization's Code of Conduct stemming from his arrest for driving under the influence last week. In addition, he has been withdrawn from the 2015 FINA World Championship and will forfeit his stipend from the organization for six months. The decision comes after Phelps was arrested for DUI in Maryland last Tuesday. Phelps also received a DUI in 2004 and was photographed smoking pot in 2009. On Sunday, Phelps tweeted, "I recognize that this is not my first lapse in judgment, and I am extremely disappointed with myself. I'm going to take some time away to attend a program that will provide the help I need to better understand myself." Phelps came out of retirement last April to start training for the 2016 Olympics.